The present invention concerns a procedure and an apparatus for the purification of air, flue gases or equivalent, in which procedure the air, flue gases or equivalent are directed into a duct or equivalent, in which procedure the air, flue gases or equivalent are ionized, and in which procedure charged impurity particles present in the air, flue gases or equivalent are attracted by one or more collector surfaces by virtue of a difference in the states of charge, causing the particles to settle on said surface(s).
GB-patent publication 1 238 438 proposes a procedure and an apparatus for the removal of dust particles from the air in a tunnel. In the procedure presented in the publication mentioned, the tunnel is provided with electrodes, to which a high voltage is applied. The electrodes charge the particles in the air in the tunnel by producing an electric field between the interior wall of the tunnel and the electrodes. Thus the charged dust particles are attracted to the interior walls of the tunnel. For the air to be sufficiently purified, it has to be very strongly ionized in order that all particles in the tunnel should be charged and attracted to the tunnel wall. Moreover, several electrodes and a long tunnel are needed.
The object of the present invention is to eliminate the drawbacks mentioned. The procedure of the invention for the purification of air, flue gases or equivalent is characterized in that the air, flue gases or equivalent are ionized by means of one or more ionizing electrodes directed at a collector surface, and that the distance between the ionizing electrode or equivalent and the collector surface as well as the difference between the states of electric charge of the collector surface and the charged impurity particles are so adjusted that the impurity particles will move essentially directly towards the collector surface and settle on it.
The preferred embodiments of the invention are presented in the other claims.
The invention provides the following advantages over current methods:
Efficient purification even in a short duct. Considerable reduction in energy consumption as compared to current procedures. The need for maintenance is reduced as the collector surfaces can be washed simply with a water jet.
Air can be purified regarding different particle sizes down to pure gases. The invention makes it possible to remove particles as small as 0.005 .mu.m and even smaller.